CHAPTER 4 INSTALLATION OF PIPE AND TESTING v1.0 4-1 CHAPTER 4 INSTALLATION OF PIPE AND TESTING OF PIPE BACKFILL Why talk about pipe in a Soils and Aggregate School? • Pipe-soil interaction

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    Why talk about pipe in a Soils and Aggregate School?

    Pipe-soil interaction is critical to successful performance of system

    Treatment of soils adjacent to pipes is different than normal placement of embankment

    Pipes must be adequately protected by soils, prior to allowing construction traffi c


    Rigid Pipe: 2% Defl ection Carries almost all the load Transfers load to surrounding soil

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    1. Pre-Constructiona. Verify Pipeb. Pipe Handling and Storagec. Minimum/Maximum Height of Cover

    2. During Construction a. Excavation b. Foundation c. Elevation d. Joints e. Connections to Structures f. Backfi ll 3. Post Construction a. Inspection and Quality Assurance


    Verify that the correct pipe has been deliveredfor the applications on your project.

    1. Metal pipe gauge Examples 12, 14, 16

    2. Metal pipe corrugation dimensions Examples 2 2/3 x ; 3 x 1

    3. Concrete pipe strength Examples Class III, IV or V

    4. pH and Resistivity - needs to be known by designer5. Maximum height of cover

    Maximum height for each type of pipe must be given

    Compare information from drainage summary with maximum cover chart for pipe to be used

    Check standards for minimum height of cover

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    Measuring CorrugationDimensions

    2 2/3 x

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    Plant stamps pipe with date cast, size, lot number Plant QC Technician inspects pipe and affi xes a QC

    stamp to the pipe


    Rigid pipe - properly fi tted, sealed with rubber, preformed plastic, mastic gaskets, oakum & mortar or oakum & joint compound

    Flexible pipe - properly aligned and joined with approved coupling bands


    Out of the way Stacked and chocked Do not stack on bells


    Do not pick up pipe by one end Use leather or nylon slings Use pipe fork for concrete Pipe Box culverts may have lift holes Pipe > 36 have lift holes Pipe < 36 shall not have lift holes

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    Make sure there is adequate cover material over the pipe before construction traffi c is

    allowed on it minimum 3 feet

    The following copied notes were included in projects beginning with the September, 1997 advertisement.

    SECTION 232.02 (a) 1. CONCRETE PIPE FOR CULVERTS AND SEWERS of the Specifi cations is amended to replace the fi rst paragraph with the following:

    1. Concrete pipe for culverts and sewers shall be circular or elliptical in cross section, either plain concrete or reinforced concrete, and of the modifi ed tongue-and-groove design in sizes up to and including 18 inches (450 millimeters) in internal diameter and either standard or modifi ed reinforced tongue-and-groove in sizes above 18 inches (450 millimeters) in internal diameter. Pipe shall conform to the specifi ed AASHTO requirements, except that pipe having an internal diameter of 36 inches (900 millimeters) or less shall be manufactured without lift holes. Pipe larger than 36 inches (900 millimeters) in internal diameter may be manufactured with lift holes provided the holes are created by molding, forming, coring or other methods to be cylindrical or conical in shape and are suffi ciently smooth to permit plugging with an elastomeric or other approved plug type. 4-11-97

    SECTION 302.03 PROCEDURES of the Specifi cations is amended to include the following:

    When lift holes are provided in concrete pipe or precast box culverts, the Contractor shall install a lift hole plug furnished by the manufacturer in accordance with the requirements of Section 232.02(a)1. of the Specifi cations. After pipe installation and prior to backfi lling, plugs shall be installed from the exterior of the pipe or box culvert and snugly seated. 4-11-97

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    EXCAVATION Locate Utilities (MS Utilities)

    Determine Location (Stake Pipe)

    Begin Excavation

    PHYSICALLY Locate Utilities

    Excavate trench, keeping safety in mind

    Sloped sides

    Trench box placed no lower than top of pipe

    FOUNDATION Explore Foundation

    Use PB 1 Standard Bedding Normal earth foundation - minimum 4 bedding Rock foundation - 1/2 per 1 foot of cover,

    minimum 8, maximum 24

    Shape bedding to minimum 1/10 diameter of pipe

    Ensure bedding is uniform and follows grade level for bottom of pipe to ensure continuous support along barrel of pipe

    Middle of bedding equal to 1/3 outside diameter of pipe, loosely placed with remainder compacted to minimum 95% standard proctor density

    Begin pipe installation downstream

    Note: The foundation is to be explored below the bottom of the excavation to determine the type and condition of the foundation. The exploration should extend to a depth equal to 1/2 per foot of fi ll height or 8, whichever is greater. If it is a routine entrance or crossover pipe 12 30 in diameter that is to be installed under fi lls 15 feet or less in height, no exploration is needed. The Contractor shall report fi ndings of foundation exploration to the Engineer for approval prior to placing pipe.

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    Foundation Materials for Pipes and Box Culverts

    Crusher run aggregate size no. 25 and 26

    Crushed glass conforming to size requirements for crusher run aggr. size no. 25 and 26 may be used for pipe not box culverts

    When standing water is in pipe foundation area, #57 stone can be used as a backfi ll in the subfoundation

    o #57 stone MUST be capped with a minimum 4 crusher run prior to placement of pipe or box culvert

    o Compaction testing on #57 stone is not required; seat stone in trench


    Invert/Outlet Elevation

    Proper Length

    Camber Suggested when possible

    Camber Provided by Materials Division

    ENSURE LEAK-RESISTANT JOINTS - JOINING PIPERigid pipe: The method of joining pipe sections is such that ends are fully entered and inner surfaces are reasonably fl ush and even.

    Joints shall be sealed with any one or combination of the following to form a leak-resistant joint: rubber, preformed plastic, or mastic gaskets from the Departments approved list; oakum and mortar; oakum and joint compound; or cold-applied pipe joint sealer.

    Rubber ring gaskets shall be installed to form a fl exible, leak-resistant seal. Where oakum is used, the unit shall be caulked with this material and then sealed with mortar or joint compound.

    Flexible pipe: Flexible pipe sections shall be aligned and fi rmly joined by approved coupling bands to form a leak-resistant joint. Note: Gaskets of pipe shall conform to the following: Rubber gaskets for ductile iron pipe and fi ttings shall conform to the requirements of AWWA C111; for concrete sewer pipe shall conform to the requirements of ASTM C443; and for other pipe shall conform to the requirements of AASHTO M198, Type A, and Section 237.

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    MINIMUM SPACING FOR PIPE JOINTS GOING INTO PRECAST UNITSPipe openings in precast drainage units shall not exceed the outside cross sectional dimensions of the pipes by more than a total of 8 inches regardless of the placement of the pipes, their angles of intersection, or the shapes of the pipes.

    When fi lling void between pipe culverts and precast drainage structures, the contractor shall use any of the following in conjunction with mortar:

    Concrete Brick Masonry Block Concrete Pipe Cutoffs Native Stone

    With exception of concrete, such materials shall be thoroughly wetted, bonded with mortar and the remaining exterior and interior voids fi lled with mortar to the contour of the precast structure.

    When precast units are located adjacent to the subbase or base course of the pavement, precast units with chambers are to have 3-inch diameter weepholes with wire cloth to drain the subbase or base layer.

    Backfi lling Considerations

    Proper haunching provides a major portion of the pipes strength and stability

    For pipe larger than 30 in diameter, work embedment material under haunches by hand (knife into area along bottom edge of pipe)

    Backfi ll below springline of pipe, compact next to pipe fi rst and work towards trench wall

    Backfi ll above springline of pipe, compact next to trench wall and work towards pipe

    Place backfi ll material directly on top of pipe to allow material to fall evenly on both sides of pipe (Do not push material from side of trench)

    Hold pipe in place when placing backfi ll to keep pipe from moving

    Dump a series of loads of backfi ll every 10-20 feet to hold pipe in place

    Leave material on top of pipe to add weight to the pipe when compacting

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    Class I backfi ll crusher run, # 25, # 26, aggregate base 21-A or 21-B, fl owable fi ll, or crushed glass conforming to the size requirements for crusher run aggr. size no. 25 and 26 from bedding to fl ow line of pipe

    Regular excavation and borrow from fl ow line of pipe to 1 foot above top of pipe.

    Box Culvert

    Regular excavation or borrow from bedding to 1 foot above top of box

    Pipe and Box Culvert Backfi ll Excavation width must be wide enough to accommodate

    compaction equip